From 48a09969e43e6564e65cc544d8760b073ac2c802 Mon Sep 17 00:00:00 2001 From: Lino Sanfilippo Date: Wed, 3 Jan 2024 07:18:18 +0100 Subject: [PATCH] serial: 8250_exar: Set missing rs485_supported flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Upstream commit 0c2a5f471ce58bca8f8ab5fcb911aff91eaaa5eb ] The UART supports an auto-RTS mode in which the RTS pin is automatically activated during transmission. So mark this mode as being supported even if RTS is not controlled by the driver but the UART. Also the serial core expects now at least one of both modes rts-on-send or rts-after-send to be supported. This is since during sanitization unsupported flags are deleted from a RS485 configuration set by userspace. However if the configuration ends up with both flags unset, the core prints a warning since it considers such a configuration invalid (see uart_sanitize_serial_rs485()). Cc: Reviewed-by: Ilpo Järvinen Signed-off-by: Lino Sanfilippo Link: https://lore.kernel.org/r/20240103061818.564-8-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/8250/8250_exar.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c index 24878d5a6a05..ada9666f5988 100644 --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -443,7 +443,7 @@ static int generic_rs485_config(struct uart_port *port, } static const struct serial_rs485 generic_rs485_supported = { - .flags = SER_RS485_ENABLED, + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND, }; static const struct exar8250_platform exar8250_default_platform = { @@ -487,7 +487,8 @@ static int iot2040_rs485_config(struct uart_port *port, } static const struct serial_rs485 iot2040_rs485_supported = { - .flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS485_TERMINATE_BUS, + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | + SER_RS485_RX_DURING_TX | SER_RS485_TERMINATE_BUS, }; static const struct property_entry iot2040_gpio_properties[] = {